Drag and Drop: how to allow dropzone to receive from multiple dragzone?

Hi,

I am currently having difficulty allowing a dropzone to receive drops from different dragzones. My requirement is simple.
Grid A: Source of all data
Grid B: Receive drops from Grid A. Grid B should allow drag and drop to itself to reorder the items.

I am currently using Ext.dd.DropZone and Ext.dd.DragZone due grids A and B have different structure. I managed to allow dragging from A to B. But how can I enable dragging from B to B (for reordering items)?

What I did

Code:

gridA.getView().dragZone = Ext.create('Ext.dd.DragZone', el, {<options>});
gridB.getView().dropZone = Ext.create('Ext.dd.DropZone', el, {<options>});
// at this point all is well. Can drag from gridA to gridB
// but as soon as I did below, I am unable to drag from A to B anymore
gridB.getView.dragZone = Ext.create('Ext.dd.DragZone', el, {<options>});

I thought I should use ddGroup so.
1. If all 3 zones have equal ddGroup - Unable to drag from A to B
2. A.dragZone and B.dropZone have equal ddGroup and B.dragZone is different - Able to drag from A to B. B items are draggable but will not be accepted by B itself.

So, is it possible in ExtJS4 to have a grid receive drops from other grids and from itself also?

I'm facing similar issue, except I have a grid and a panel. I want to be able to drag from grid to panel, and also reorder components inside the panel. If I add a DragZone for the panel, then can't drag from grid to panel anymore.

The solution that worked for me was create another ddGroup different from the first and add container B's drag zone and drop zone to the new group. One caveat is that this worked for me (assume 'this' is container B):